This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: To explore the use of human and monkey embryonic stem (ES) cells derived dopamine neurons for cell replacement therapy in Parkinson's disease. Cell replacement strategies have been proposed as a treatment for advanced Parkinson's disease. Two years ago, we began a pilot study using dopaminergic-human ES cells to assess viability and safety in the monkey brain. Last year, we analyzed the data. Our results suggest that differentiated hES cells in the monkey brain are able to elicit an immune response that affects their dopaminergic characteristics and survival. This research used Animal Services, CPI, Stem Cell Resource, and Pathology Services. Publications pending.